The option to offer Free trials in the app store would remove the need for in-app purchases for a lot of non-abusive apps and games. That would definitely be the case for all the apps we publish [1].

Users simply don't want to pay money to try out paid apps, unless they have tons of 5 star reviews or are recommended by friends or media. And why should they?

In the absence of free trials we are stuck with offering "free" apps with in-app upgrades.

[1] https://itunes.apple.com/us/app/life-is-beautiful-get-daily/...